Broaching machine



y 1936. F. s. FLOETER BROACHING MACHINE Filed May 18, 1935 INVENTORFREDERICK 3. FLOETER Af'r RNEY Patented May 5, 1936 PATENT OFFICE2,039,480 nnosonmo MACHINE Frederick S. Floater, Saginaw, Mich.,assignor to Wickes Bros., Saginaw, Mich., a corporation of MichiganApplication May 18, 1935, Serial No. 22,136

3 Claims.

This invention relates to improvements in metal forming machines forturning and facing work pieces by broaching.

.The general practice in turning engine crank shafts and the like bybroaching has heretofore been to rotate the work on a stationary axisand to traverse a long toothed broach bar tangentially past the rotatingwork pieces in operative engagement therewith, the rotational'speed ofthe work and the longitudinal movement of the broach being such that thework piece made approximately one revolution while in contact with eachsuccessive cutting tooth on the breach. Suc-' cessive teeth were steppedor oliset relatively to each other so that each removed a shaving ofmetal from the surface of the revolving work piece and all the shavingshad the same thickness. On account of the stepwise location of the teetheach traveled in a plane of its own, ofl'set from the plane of travel ofadjacent teeth by an amount ,equal to the thickness of the shavings.

In such known machines the work was finished during a singlelongitudinal movement or traverse of the broach, and to start theturning operation the work piece had to be'brought up to the broachwhile the breach was at the commencement of a working stroke. Idlestrokes alternated with working strokes.

To produce a true cylindrical surface on the completed work piece thelast few cutting teeth on the broach bar were made without offset, thatteeth.

mentioned disadvantages are overcome by provid ing a broach bar in whichthe teeth are According to my present invention the above ot stepped inrelation to each other and they ca be all alike. All the teeth move in asingle p ane instead of in a great number of individual p 'allel planesas was heretofore necessary in order to give the desired cutting feed.The work piece, instead of being rotated ina fixed axial pos ition,

is arranged and operated in my machine fso as to 3. move toward thecutting teeth during its rotation.

Such approach may be at any predetermined desired feed rate andconsequently the amount of total feed-in movement can be regulatedaccording'to the amount of metal which it is desired to remove from thework piece. This feature distinguishes from earlier machines wherein agiven broach was limited to removing a predetermined maximum thicknessof metal or some less amount.

Moreover, my improvement enables the broach to cut during both of itstraversing movementsor strokes when desired, thus eliminating idlestrokes. The work piece is rotated in the direction indicated by thecurved arrows, Figs. 1, 2, and 4, at a peripheral speed greater than thespeed of linear travel of the broach. Thisspeed difierential enables theteeth to out and clearproperly on the up-stroke of the broach, Fig. 4,as well as on the down stroke. Cutting may continue on severalsuccessive strokes if necessary, or until the work pieceis reduced tothe required size, irrespective of reversals of motion at the ends ofthe strokes. A finished workpiece can be removed and a new one insertedwithout stopping the movements of the broach, thus saving time which wasformerly wasted in waiting for a one-way broach toreturn to startingposition.

In view of the foregoing explanation it will be seen that the objects ofmy invention are, to

simplify the design and reduce the expense of constructing machines forsuch kinds of work; to simplify the arrangement of the broach teeth andrender them less expensive to renew; to greatly increase the rate ofproduction of themachine by reducing the time required for putting ,inand taking out the work; to enable the rate of cut and the depth of cutto be varied at will; and in general to advance the art of broaching inthis class of work.

The means by which I attain the foregoing desirable results and othersthat will appear later in the specifications, although simple, is ofgreat importance, especially in the automotive engine and otherindustries where accuracy and high rate of economical production arefactors.

In the accompanying drawing, I Fig. 1 is a side view, partlydiagrammatic, of a machine embodying my invention,

Fig. 2 is a front view,

Fig. 3 is a top plan view,

Fig. 4 is a diagrammatic side view, showing the operative relationshipbetween the reciprocatory breach and the work piece.

My improved machine consists of a toothed bar I mounted in ways 2 inwhich it is slidable back 1-;a'nd iorth in'the direction of its l Thebroach may be actuated by any suitable driving mechanism. In the machineherein illustrated as a preferred embodiment of my claimed invention thedriving m comprises a motor land a train of gearsoperatively connectingthe motor. to a screw bolt '4 on which is a'threaded travellug nut I,fixed to the broach bar I, or to aslidable bar-carryin plate la whichismounted in theways 2 of irame it. v A thrust bearing 6 is" provided totake the end thrust of the traversing screw 5. s f I a In operation themotor '3 rotates a pinion I,-

' 1 an idle pinion and agear a. -Gear a turns the screw and nut 5 movesthe breach bar endwise; The rate of traverse is made appropriate tothekind and size of the work piece, its-speed of a,oso,iso" I changesinrthe speed of longitudinal travel of the breach I, and in the speed ofrevolution oi the work W, and in the speed of teed-in movement of thework toward the teeth It, are not shown herein because such devices areknown .to those skilled. in the art and-their specific structure formsno new part of my invention as set forth in the claims.

- By suitably regulatingthe rate of movement of the chucks l2, l3 towardthe ,teeth iii the depth of cut-per tooth can be varied tosuit the arotation and to the pitch oi the broach teeth ll, all according tovknown practice, in the art oi. broach turning.

I The direction of travel reversed at. any point in the stroke, as wellas at; the ends, enabling the cutting teeth to be used matic reversal-oithe motor 13.

"mechanism equally. That may be accomplished- .by auto- The reversing Iis ,not illustratedhere, being well known;

" The broach teeth are preferably all of of the breach may.

height; and their cutting. edges ii, which extend across thefa ceoi thebari, approximatelyv at right angles to the direction of its length,move I in a common planes-1i, the position of which is fixed by the ways2. The work piece W, which may be an engine shaft whose bearings are tobe turned and whose cheeks areto be iaced, is

mounted on suitable opposed center bearings, as chucks" i2, ilLj Theaxis common to the chucks and the work piece ,W is kept parallel withthe plane defined by the cutting edges llctthetceth.

To bring the work piece into and-awayirom ment of. the work W whilecontinuing its axial.

inder. 22.

size 0! the work pieces and the kind of inaterial of which they aremade, and such teed-in rate can be changed at will by controlling it atcyl- Cutting. can be started on the work piece W at any point on-h ar[along its row of cutting teeth. Also; a flnished'work piece can beremoved from the chucks and a new rough piececanbe mounted thereon andfedto the teeth without stopping the reciprocation oi the broach bar,thus saving time and greafly increasing the rate of output of themachine.

A finishing out can be oi the irregularities of the work piece andthereby produces a perfectly cylindrical product, and this can be donewithout employing a special set of finishing teeth for that purpose, ashas been the practice heretofore. To iinish, it is only necessary tohalt the transverse ieeding-in moverotation and continuing alsothe-endwise movementoi the broach.

- The broach bar I may be equipped, as shown,

. with teeth on its front face on1y,'or its sides may be providedwithcutting teeth ior' facing oi! .the cheeks or crank arms on engineshafts, or for facing-flanges on the work pieces; also en thateliminates all these rows of front teeth It and side teeth 33 I Iengagement with thejteeth and to. regulate the -erably employed. "Thechucks i2, llfare mount depth of cut, the lollowing mechanism is prefedon movablehousings My" capableoi'being advanced-simultaneouslytoward theteeth ll during reciprocation of the brooch. In the i'orni thehousingsll, 'II are pivoted .to the ltramework "at "and II; r

and back deeding movements, indiinl 'lgs. 1"and 4 by the arrows r, areim- T partedto each housing by-means' or an arcuate toothedrack I fixedto the housing and meshing with-a pinion 2. which is mountedinflxedbearings-onlthe'irame It." The pinion 20 can be rotated alternately inopposite directions by:

nieans-o! {trackll or equivalent gearing actuf Flo atedby'a such-as anhydraulic cylinder-I2. mounted on a fixed support. -Mov ement or therack up or down, 1,.rotates pinion "and thereby rocks the housing? I,

planes so as to produce piece.

may be shaped at their corners defined by inter-- Unusual capacity,speed and adaptability to varieties of work-are characteristics of thisi118? chine and will be appreciated when it is observed 40 filets in thework that the breach can cut on both strokes, viz. up-..

and-down in the vertical type 01' machine shown in the drawing.- No timeis lost in returning the breach, and no gearing-is required forsuchpurll tothe, right or left, thus feeding theworkwtowardorretractingltfronithe feethil.

-- The center bearings or-ohucks l2, l8 andthe l -k pleoe w mkept inrotation in one direc-'.

tion, as indicated by theicurved arrows, ,by means of a suitably drivenshaft, a pinion 24 on the shalt, anidle a mounted i fixed, bearings onthe (tame, and intermediate gears 28 and 21.

I llflthatcarrythechucb Theworkwishererepresentedas'heing three breaches",jl, II, on plate is.

2care rotatable n the" pivot shaft 11 ornouslnss. andmesh with gearsllwhich-are- Moreover, the depth or cut cylindrical piece operated n posesas in earlier machines. The out can begin at any podtion oithe'broach,-so no specific repositioning mechanism is required. I

. This machine is simple in its mode of operation, relativelyinexpensive tomanuiacture and keepin repair, is so designed andorganized as to be built exceptionallystrong and rugged with aofmaterial'. -It has great speed and producing capacityi and thebrooches, having all of'th e same height and shape, are less constructand keep in repair than thoseinwhich theteeth areprogressively pertooth,being easily controllable and i --commercial1an8eoi.themaer-types-whichdidnotemhodythat the relatively-rapid rotation otthe -;-ror'r ed1n thewot 'n e u w above described,

j slowup-and-dcwn movement oi.

worki at a'rate'appropriate'toproduce the requisite, or speed, andthe-coincident ieedin'goi workpiece "teeth are co-operative in ob I of Iis to be understood that a known slide type of feeding device may beemployed, or anyequivalent means may be used without departing from theinvention as set forth in the claims.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

1. In combination, a broach bar arranged and actuated for lengthwisereciprocating movement and having spaced teeth whose cutting edges aremaintained in a single plane during said movement, opposed centerbearings adapted to support between them a work piece whose axis ismaintained in parallelism with said plane, rotatable means actuatingsaid bearings and work piece, and feeding means operative to move therotating work piece axially sidewise toward and away from said teethduring the reciprocation of the broach.

2. A structure as set forth in claim 1 wherein the common axis of saidcenter bearings and work piece is maintained parallel with a planedefined by the cutting edges oi the teeth and is also movable sidewisein directions substantially perpendicular with the plane of said cuttingedges, and means for varying the rate of such sidewise movement in sucha manner as to regulate the rate of cutting.

3. In combination, a broach mounted for lengthwise reciprocatorymovement and having teeth spaced apart, the cutting edges of said teethbeing disposed in a single plane and arranged and actuated forreciprocating cutting movements in said plane in both directions of saidlengthwise travel, supporting chucks for a work piece, powered gearingadapted to impart movements at various rates of speed to said chucks insidewise direction simultaneously toward the said plane of the cuttingedges during the reciprocating move-' ments of saidbreach in bothdirections of its travel.

FREDERICK S. FLOE'I'ER. 20

